1. Field of the Invention
The present invention relates to a solar battery module, and more particularly to a solar battery module which can swiftly discharge a puddle of rainwater collected on its light-receiving side even when placed substantially horizontally.
2. Description of the Related Art
As shown in FIGS. 7 and 8, a solar battery module 100 usually comprises a solar battery panel 108 and a frame body 105. The solar battery panel 108 includes: a front cover 101; a solar battery 102 composed of a plurality of solar battery cells 102a; a back cover 103; and fillers 106a and 106b. The front cover 101 serves to protect the light-receiving-surface side of the solar battery 102. The solar battery 102 for converting sunlight into electricity is composed of a plurality of crystal solar battery cells 102a connected in series. The back cover 103 serves to protect another side of the solar battery 102 opposite to the light-receiving-surface side, i.e., the back-surface side of the solar battery 102. The filler 106a is filled in between the solar battery 102 and the back cover 103. The filler 106b is filled in between the solar battery 102 and the front cover 101. In this way, the solar battery panel 108 is constituted by laminating the front cover 101, the filler 106b, the solar battery 102, the filler 106a, and the back cover 103 on one another in this order. The solar battery panel 108 thus fabricated is given a substantially rectangular shape.
The frame body 105 is composed of a plurality of aluminum-made frame members 105a, 105b, 105c, and 105d, and is attached to the solar battery panel 108 so as to surround its outer edge. The frame members 105a to 105d are each bonded to the outer edge of the solar battery panel 108 with adhesive 104. The watertightness of the solar battery 102 is attained by the use of the fillers 106a and 106b, which are so filled as to sandwich the solar battery 102, and the adhesive 104 used for attachment of the frame members 105a to 105d. The adhesive 104 is made of butyl rubber, expanded EPDM, or silicone resin. Moreover, to improve the watertightness of the solar battery panel 108, a filler 7 is filled in between the outer edge of the front cover 101 and the frame members 105a to 105d. 
A solar battery module having such a configuration as described above is usually mounted via a frame member on a platform placed onto a building roof. In order to obtain the maximum electrical generating capacity, an angle at which the solar battery module is mounted (a mounting angle) needs to coincide with the latitude of the placement location. In Japan, the mounting angle is generally set to a range of about 20 to 45 degrees.
Incidentally, there are a wide variety of building roofs. In particular, residential buildings or the like typically employ a roof having a slope, such as a hip roof or gable roof. In a case where the solar battery module is mounted on such a roof, since the mounting angle of the solar battery module is identical with the inclination angle of the roof, in the event of rain, rainwater flows on the light-receiving surface of the solar battery module, and therefore it never occurs that the rainwater remains on the light-receiving surface after the rainfall. On the other hand, factory or public buildings typically employ a flat roof with no slope. Thus, in a case where the solar battery module is mounted on such a flat roof, the solar battery module is mounted substantially horizontally. In this case, it is inevitable that rainwater remains on the light-receiving surface of the solar battery module after the rainfall. For example, it has been confirmed that, even though the height (distance) between the front cover to the top end of the frame member was made as small as 0.7 mm, an about 10 centimeters long puddle of rainwater remained on the solar battery module in the inclination direction thereof.
If rainwater remains on the light-receiving surface of the solar battery module as described above, dirt and dust contained in the air collect in the remains of the rainwater. After the rainwater evaporates, the dirt and dust are deposited on the light-receiving surface. The dirt and dust remaining on the light-receiving surface are generally not rinsed away by subsequently-occurring rainfall. Thus, whenever it rains, dirt and dust accumulate on the light-receiving surface. The increasing accumulation of dirt and dust gradually prevents the light-receiving surface from receiving sunlight, with the result that the amount of light received decreases, and this leads to reduction in the electrical generating capacity.
The above-mentioned problem can be solved by swiftly discharging a puddle of rainwater out of the light-receiving surface. However, in conventional solar battery modules, while due consideration is given to protecting the solar battery module from intrusion of rainwater, no consideration is given to discharging rainwater remaining on the light-receiving surface out of the solar battery module placed horizontally, or substantially horizontally.
The invention has been made to solve the above problem, and accordingly its object is to provide a solar battery module which is, although being placed horizontally or substantially horizontally, capable of swiftly discharging rainwater from its light-receiving surface after rainfall and maintaining electrical generating capacity of a desired level.
To achieve the above object, the invention provides a solar battery module comprising:
a solar battery panel including a solar battery composed of a plurality of solar battery cells connected in series;
a frame body for surrounding an outer edge of the solar battery panel; and
rainwater guiding means, disposed in the frame body, for guiding rainwater collected on a light-receiving surface of the solar battery module to an outside of the frame body.
According to the invention, even if the solar battery module is placed horizontally or substantially horizontally, rainwater collected on the light-receiving surface can be discharged to the outside of the solar battery module by the rainwater guiding means.
In the invention, it is preferable that the rainwater guiding means is constituted by a notch with an open end facing toward the light-receiving surface. In this case, the rainwater collected on the light-receiving surface flows into the notch, overflows the notch to the frame body, and is then guided toward the outer side of the frame body. Thereafter, with this water-guiding effect, the rainwater contained in the notch is guided toward above the frame body on the principles of siphon action. In this way, the rainwater can be discharged out of the solar battery module.
In the invention, it is preferable that the frame body is formed in a substantially rectangular shape and the notch is formed in a corner of the frame body. In this case, even though the solar battery module is diagonally inclined in one direction, the rainwater collected on the light-receiving surface flows into the notch located lowermost, overflows the notch to be guided toward the outer side of the frame body. Thereafter, with this water-guiding effect, the rainwater contained in the notch is guided toward above the frame body on the principles of siphon action. This enables the rainwater to be discharged out of the solar battery module.
In the invention, it is preferable that the notch is covered with a hydrophilic film. In this case, the rainwater which flowed into the notch is guided while being admitted to the hydrophilic film toward above the frame body. This enables the rainwater to be discharged out of the solar battery module.
In the invention, it is preferable that the maximum width of the open end of the notch is set to exist within a range of 1 mm to 5 mm. This makes it possible to prevent intrusion of water into the frame body, to prevent reduction in the torsional strength of the frame body, and to perform the discharge of the rainwater-remaining on the light-receiving surface.
In the invention, it is preferable that the rainwater guiding means is constituted by a slant surface extending from a top surface of the light-receiving surface to a surface of the frame body, the slant surface being formed by filling a water-repellent filler, such as silicone resin, in an outer edge portion of the light-receiving surface. In this case, the rainwater remaining on the light-receiving surface, which flows toward below the solar battery module arranged at an angle, is repelled by the slant surface so as to be guided toward above the frame body. As a result, the rainwater is discharged out of the solar battery module.
In the invention, it is preferable that the slant surface is wholly covered with a hydrophilic film. In this case, the rainwater remaining on the light-receiving surface, which flows toward below the solar battery module arranged at an angle, is admitted to the hydrophilic film so as to be guided toward above the frame body. As a result, the rainwater is discharged out of the solar battery module.
In the invention, it is preferable that the light-receiving surface is formed in a substantially rectangular shape, and the slant surface has a part corresponding to a corner of the light-receiving surface, which part is covered with a hydrophilic film. In this case, even though the solar battery module is diagonally inclined in one direction, the rainwater remaining on the light-receiving surface, which flows toward below the solar battery module arranged at an angle, is admitted to the hydrophilic film covering the lowermost slant surface so as to be guided toward above the frame body. As a result, the rainwater is discharged out of the solar battery module.
As described heretofore, according to the invention, even in a case where the solar battery module is used for an industrial solar electric power generation system which is generally placed horizontally or substantially horizontally, the rainwater remaining on the light-receiving surface can be discharged out of the solar battery module without degrading the strength of the solar battery module. This prevents the rainwater from persistently remaining on the light-receiving surface after rainfall. Thus, it never occurs that dirt and dust contained in the air collect in the rainwater remaining on the light-receiving surface after rainfall. As a result, it is possible to protect the light-receiving surface against deposition of dirt and dust, and to prevent reduction in the electrical generating capacity.
The invention is also suitably applicable to a light transmitting type solar battery module. In that application, since contaminants, such as dirt and dust, deposited on the light-receiving surface are removed, light transmission is facilitated. Thus, not only the electrical generating capacity, but also the appearance is not impaired.